Or search for the wave in the Navigation panel or type in the search criteria in the Inbox panel search box. Either way you should use the following text:

with:public tag:#leankanbanX
with:public tag:skillsmatter

Until you follow a wave or are added by someone, you need to include the with:public, otherwise google wave will just look at your inbox.

Once you are following the wave you can find it in your overcrowded inbox by using tag:#leankanbanX or tag:skillsmatter GoogleWave accounts are by invite only at present, if you need an invite please let me know.